Why Do Potato Leaves Turn Yellow? Causes and Solutions

Potato is also known as the Irish potato. Potatoes contain a large amount of starch, and starch is the main energy we get from eating potatoes. They also have a relatively high protein content, which can promote human growth. Growing potatoes has become one of the poverty-alleviation projects for many people, but many friends do not have a correct growing method. This leads to many problems during cultivation, such as yellowing leaves, which is one of them. So what causes the leaves to turn yellow? Let's take a look below!

1. Late blight

Late blight is one of the more common diseases of potatoes. After a plant is infected with late blight, the disease starts from the lower leaves. Many water-soaked dark spots appear on the surface of the diseased leaves, then gradually expand, and the spots merge together to form patches of varying sizes. The leaf edges of the patches begin to turn yellow and spread toward the center, causing the leaves to turn yellow. Late blight can be treated with agents such as cymoxanil plus mancozeb, and attention should be paid to prevention first.

2. Verticillium wilt

Verticillium wilt is a soil-borne disease that attacks the roots of the plant and then slowly spreads upward. After the roots are infected, the pathogen destroys the vascular bundles in the plant, greatly hindering nutrient absorption and transport. When the plant lacks nutrients, the leaves gradually turn yellow starting from the veins and finally become yellowish-brown. After the disease occurs, the growth of the plant becomes extremely slow, the whole plant appears withered and weak, and it dies in the later stage.

3. Early blight

Early blight, like late blight, harms the leaves of the plant, especially old leaves that have not been removed in time. After the leaves are infected, various dark-colored spots appear, which then gradually expand into patches. The leaves with patches begin to lose chlorophyll and turn yellow, and finally the entire leaf loses its green color, dehydrates, and dies. The tuber bulking stage is a period of high incidence of early blight, so agents such as mancozeb should be sprayed in advance for prevention.

4. Potassium deficiency

Potatoes have a relatively high demand for potassium. If potatoes lack potassium during growth, the leaf tips and leaf edges will rot and gradually change from green to yellow. When potassium deficiency is severe, the leaves curl together, as if dried by the sun, and crumble at a pinch. It also increases leaf drop, greatly affecting the growth of the plant. We should promptly spray agents such as phosphorus-potassium power to supplement potassium.

5. Nutrient deficiency

It was just mentioned that potassium deficiency can cause leaf yellowing. In fact, a lack of various nutrients can cause this phenomenon, but because potassium deficiency is relatively common, it was discussed separately. Many farmers do not reasonably control the nutrient ratio in fertilizers when fertilizing, resulting in nutritional imbalance in plant growth. For example, a lack of nitrogen, sulfur, and enzyme can cause various abnormal conditions in the leaves. If these elements are not supplemented in time, the whole plant will eventually show symptoms of nutrient deficiency.

The above are several causes of potato leaves turning yellow. Most are caused by diseases, and the threat of diseases to plants goes far beyond these. After the leaves turn yellow, photosynthesis decreases, the plant cannot increase its nutrient accumulation, tuber bulking is hindered, tuber quality is affected, and one's own economic interests are also threatened to a certain extent. That is all for today's introduction. Everyone should reasonably control the nutrient ratio of fertilizers to reduce or eliminate this phenomenon.